Listen Technologies LR-42 Stereo Receiver User Manual


 
110
LA-140
LT-82
Design Guide
Design Guide
LR-42/44
If you have Auto-Seek disabled (default setting) the unit scrolls to the next channel with each press of the
Select button. If, for example, you have a two channel system you can use this feature to “lock out” the
other two unused channels so that the user will not have to scroll through them to get to the channels with
a signal. If you have Auto-Seek enabled and are using less than four channels, you can use the Channel
Lock-Out mode to ensure the receiver will not stop on a channel without a signal. If, for example, you are
XVLQJ$XWR6HHN0RGHDQGKDYHWZRFKDQQHOVDFWLYHFKDQQHOVRQHDQGIRXUDQGÀQGWKDWRIWHQWLPHV
when the unit seeks for channel four is stops on channel three, you would use the Channel Lock-Out Mode
to eliminate the problem.
When to Lock Out Channels
Channel Lock-Out (Default is All Channels Available)
Channel Lock Out function
This function is used to lock out channels from being accessible to the user when the Select button
is pressed or when the unit is seeking for a channel in Auto-Seek Mode. This function is different
from the Channel Lock function in that this function removes channels from being selectable
ZKHUHDVWKH&KDQQHO/RFNIXQFWLRQKROGVWKHXQLWRQWKHFXUUHQWFKDQQHO%\XVLQJWKLVSURJUDP
mode you can lock out any combination of channels.
Stereo Mode (Default is OFF)
Stereo Mode Function
This function must be set to match the type of signal that the receiver is receiving. If the receiver is receiving a
mono signal this function must be OFF. If the receiver is receiving a stereo signal this function must be ON.
When to enable Stereo Mode
Stereo Mode must be enabled if the receiver is receiving a stereo signal from the transmitter.
It is recommended to enable the Auto-Seek feature in applications where a user will be moving from one area
to another and does not want to have to manually change the channel on the receiver in each new area. Also
if it is desired that the Select button act as a “seek” button instead of a manual scroll to the next channel button,
Auto-Seek should be enabled.
If the receiver has been locked on a channel the lock will take priority over Auto-Seek.
When to Enable Auto-Seek
Priority
Auto-Seek (Default is O)
Auto-Seek function
Upon power-up with the Auto-Seek feature enabled the unit will search for a channel with a signal present. If
DVLJQDOLVIRXQGWKHXQLWZLOOVWRSDQGVWD\RQWKDWFKDQQHO,IWKHXQLWGRHVQRWÀQGDVLJQDOLWZLOOFRQWLQXHWR
seek until one is found. If the unit is on a channel with a signal it will remain on that channel until the signal is not
detected for a short time at which point it will automatically seek for another channel with signal. If the Select
button is pressed when the unit is on a channel it will seek for the next channel with a signal.
For maximum range the squelch setting should be set to a low level (0, 1 or 2). However when setting the
squelch level low the reliability of the squelch setting is compromised and will lead to radio noise being
heard in the earphone when signal strength is low. If no radio noise is desired to be heard the squelch
setting should be set to a tighter position. However when setting the squelch level high the receiver will
have reduced range due to the audio being cut-off when signal is low. See “Programming Unit” section
for instructions on how to adjust squelch setting.
When to Adjust Squelch Setting
Squelch Setting (Default is 3)
Squelch Setting
The purpose of squelch is to mute the audio output of the receiver when the signal from the radiator(s) is
turned off or is too weak to be received. Without squelch you would hear radio noise in your earphone.
The squelch on your receiver can be adjusted so that it will mute at varying levels of signal strength. There are
16 settings that the squelch setting can be set to. The lowest squelch setting (no squelch) is “0” and the
tightest squelch setting is “15.” The default setting is “3.”
Programmable Features Detailed Descriptions